Field in sight,
If you went FULL TIME learning in the UK you would probably just about finish your PPL in the same time as long as you pick a reasonable time of year, if you are only expecting 2-3 cancellations in that time you can't have been making enough bookings. In the days of Air Cadet flying scholarships (30 hrs flying in my day) 4 weeks were allowed to complete which was usually enough. Provided you don't turn up last minute expecting to start (how many people would head to the US without booking well ahead?) most of the schools I know could fit people in on an intensive course, AND with the same instructor for most of it.